The present invention relates to computer systems. In particular, it relates to an assembly in which a printed circuit board is attached to a computer""s chassis in a unique way.
When assembling a computer system, it may be necessary to attach one or more printed circuit boards (xe2x80x9cPCBsxe2x80x9d) to a computer chassis. This is typically done by using a number of screws to connect these components together. When those screws comprise discrete fasteners, they can be dropped into the chassis during computer assembly or PCB field replacement. Having loose screws move about a chassis is undesirable as they can cause short circuits. For that reason, captivated fasteners may be required for PCB retention, e.g., for field replaceable parts that are used in back-end servers.
Such fasteners can be designed into the PCB. The resulting assembly, however, requires the PCB to include large mounting holes, which impose unfavorable layout constraints and/or require large trace and component keep outs to be positioned around them. In addition, the PCB can be damaged when the fastener is pressed into it. An alternative, in which PCB retention screws are snapped into large holes that are formed in the board, presents similar disadvantages while requiring the back of the board to accommodate the fastener""s protruding snap feature. Another technique, which is somewhat cumbersome to apply, consists of attaching the PCB to a sheet metal carrier using loose screws, then connecting the PCB/sheet metal carrier assembly to the chassis with screws that are captivated within the sheet metal carrier.
Accordingly, there is a need for a computer assembly with an improved mechanism for attaching PCBs to a computer chassis using captivated fasteners. There is a need for such an assembly that can be easily put together, and which does not require PCBs to include large mounting holes or large trace and component keep outs. The present invention provides such an assembly.